For those of you that have tried thyroxine, how did you respond? I responded horribly. More energy but my heart took off. It is my conclusion that I have some sort of genetic defect in either the expression of or the gene itself for adrenergic receptors. Therefore, the body naturally seems to put up thyroid resistance to spare the heart and organs from overworking on adrenaline. This is just a theory - but given the supersensitivity to adrenaline and POTS most of us exhibit, it could explain a lot. By adding a strong beta and alpha blocker like COREG with high dose thyroxine and other hormones that may be deficient I am thinking many cases of fibromyalgia can be pulled out of.